Thysanocarpus laciniatus is a species of flowering plant in the family Brassicaceae known by the common name mountain fringepod.

It is an annual herb producing a slender, branching or unbranched stem 10 to 60 centimeters tall.

It is somewhat waxy in texture and generally lacks hairs.

The inflorescence is a raceme of small whitish or purplish flowers.

The fruit is a flattened, rounded or oval disclike capsule with a thin wing around the edge.